Manufacture of carbon.



' lTED STATES I \VILLIAM- J. BURKE, OF SCRANTON,

PENNSYLVANIA, ASSIGNOR OF ONE- HALF TO HENRY A. KAUFHOLD, OF SAME- PLACE.

MANUFACTURE OF CARBON.

SPECIFICATION forming part of Letters Patent No. 655,920, dated August 14, 1900. Application filed December 16, T899. Serial No. 74 ,573. (No specimens.)

To all whom it may concern.-

Be it known that I, WILLIAM J. BURKE, a

citizen of the United States, residing at Scranton,-Lackawanna county,Pennsylvania, have invented certain new and useful Improvements in the Manufacture of Carbomof which the'following is a specification.

My invention relates to carbonfor electrical and other purposes.

. The invention consists in a carbon for electrical, metallurgical, and other purposes -1nanufactured from impalpably powdered anthracite coal.

Heretofore in the manufacture of carbon for electrical purposes-such as are light points, contacts, brushes, &c.-coke from bituminous coal and coke from petroleum-stills and gas-retorts have been generally employed as a base with varying degrees of success. v

just enough of an ole-aginous substance, such as gas-tar, to moisten ordampen the powder. These ingredients are treatedin the following manner: The anthracite coal is first reduced to an impalpable powder or the impalpable powder around anthracite-coal breakers or washeries may be employed, and this powder is heated in an iron vessel having a loose cover for the escape of gas or vapor. This powder is heated to about 125 to 150 Fahrenheit, and the heat is kept up until the mass is evenly heated throughout. The tar or other oleaginous substance is placed in a sepa rate vessel and heated to the same degree as the powder. Just enoughof the heated tar is now added to the powder to moisten or The filled molds will now have their tops ap- I plied, and the tops will be loosely covered with clay or other suitable material and placed in a retort, oven, or furnace, where they are subjected at first to a low heat which is gradually increased to about 210 Fahrenheit, at which it will be maintained for from ten to twenty-four hours, according to the kind of carbon required; It will be seen that the material being treated is protected from the atmosphere and from the direct action of the heating medium as it is confined within the molds. protecting the material in the molds changes take place in the constitution of the coal and cause it to cake, after which the heat is steadily increased until it reaches a degree equal to red-hot iron, at which it is continued until all impurities are driven ed in the form of gases, when the heat is turned off and the molds and their contents are allowed to gradually cool. The result attained will be found to be an electrical conductor of substantiallypure carbon from anthracite coal, which c0n= tains prior to this treatment only about eighty per cent. carbon and is a non conductor of electricity.

It will be seen that all necessity for coked material at the beginning of this process is obviated, as the coking and converting into carbon take place in the molds.

In testing my new carbon I find that it works as well in the inclosed arc-lamp'as in the open arc-lamp, in both of which it proved highly satisfactory.

I do not confine myself to any particular 7 By thus graduating the heat and r use, but claim the article for any andall purposes, nor do I restrict myself to the particular method herein described for forming it.

What I claim, and desire to secure by Let- 5 ters Patent, is-

1. As a new article of manufacture, carbon for electrical and other purposes manufactured from impalpably-powdered anthracite .coa

IO 2.- As a new article of man ufactnre, carbon for electrical and other purposes, manufac- In testimony whereof I affix my signature in presence of two witnesses.

WILLIAM J. BURKE.

' Witnesses: GRAFTON L. MCGILL, GEO. II. EVANS.

suitable receptacle. 1 5 

